But messengers are people
Yes and no. Yes as they are born human as we are, yet the Spirit they are born with is not. They are born of the Holy Spirit, we are born of the Human Spirit.
The Bible story of the Virgin Birth is a Spiritual Metephor of how a Messenger is not a human like us, even if we see they are born of a Mother, as we all are.
As you can see, this discussion would require that we acknowledge that there is a Spirit behind creation.
This is how the Bab offered it to us
"The substance wherewith God hath created Me is not the clay out of which others have been formed. He hath conferred upon Me that which the worldly-wise can never comprehend, nor the faithful discover."
— Epistle to Muhammad Shah, Selections from the Writings of the Báb
That is one of the proofs of a Messenger. They will have innate knowledge of all things, but have never studied like other people.
Regards Tony